hey guys,
my first post on this forum :P

I have a Marshall MG412A and hate the crappy speakers inside it.
Im thinking of replacing them with Celestion G12T-75's from a 1960a.

The MG412A is compact and smaller than the 1960a, so I think the speakers are spaced closer together.
will this make a difference to the sound?
why not just use the 1960a cab?

82' Gibson Les Paul w/ EMG KFK
Schecter Limited Edition C-1 Artist
Fender Fat Strat
B-52 AT100 Head
B-52 AT100 Cab
Blackstar ht-distx
Boss NS-2
Boss TU-2
Yes it will make a difference, if you get the Theile/Small parameters for both drive units from drdecibel at Celestion I can tell you how much.

Why not just sell your speakers and buy the ones you want or build a cabinet from scratch if you want a project?
well thats exactly what im doing, buying the new speakers and getting rid of the old ones.
i think i should rephrase the question.

what i wanted to know was what the difference in sound would be between the 1960a cab and the MG cab both fitted with G12T-75's